nRF52832 bonding loss

RE: nRF52832 bonding loss

Ken314 — Fri, 16 Jun 2023 20:10:48 GMT

We may be closing in on this one. With multiple systems running and logging using J-Link RTT Viewer we've captured two bonding losses. In both cases there was a message in the RTT viewer log indicated there was a "pin reset". (We report the contents of the RESETRES register at boot). This is a bit perplexing as the units were on a bench in the lab and both of the resets occurred overnight when no one was around. While the nRF52-dk was connected to the 52832's SWD pins, the reset pin is not.

The PSELRESET registers are set to the default values, While I haven't found it documented in the manual, it appears the reset pin uses the same ~16k ohm pull-up as when the pin is used as a DIO. So I'm having trouble understanding how these resets occur.

Any thoughts?

Thanks

RE: nRF52832 bonding loss

Daniel Veilleux — Wed, 07 Jun 2023 22:00:58 GMT

I mean the app on the nRF52832. It's common for devices to store reset counts, operational hours, DFU update history, user settings, etc. in flash. Whether or not you use flash data storage at all is interesting -- if not then SDK code is the only fstorage user. If you look at an affected device and notice that e.g. all of the user settings are back to their defaults then that would be a clue.

RE: nRF52832 bonding loss

Vladislav M. — Wed, 07 Jun 2023 20:09:27 GMT

Hi Daniel,

We haven't yet captured this occurrence since it happens rarely. We still don't have logs but we are working on it.

When you ask "Does the app store its own data to the flash?" do you mean mobile app or the app running on EM?

If we connect to one of the affected devices after this had happened, we can't determine if non-volatile storage had been reset. If it happens while connected to the debugger, we can capture it in the log.

RE: nRF52832 bonding loss

Daniel Veilleux — Tue, 06 Jun 2023 20:43:11 GMT

The most likely cause for losing the bonding info on the nRF52832 would be an issue with the non-volatile storage. Does the app store its own data to the flash? If you connect to one of the affected units would it be possible to determine whether or not the non-volatile storage had been reset recently? Also, is there any log information available?

RE: nRF52832 bonding loss

Ken314 — Tue, 06 Jun 2023 18:53:48 GMT

Unsure. The phone goes back to it's unpaired state, and the board starts blinking it's LED indicting it's advertising. Only one connection is allowed at a time - the board stops advertising when it's bonded. The only mechanism for unbonding that the product supports is an intentional one where the phone sends a command to the board.

Thanks

Ken

RE: nRF52832 bonding loss

Daniel Veilleux — Tue, 06 Jun 2023 18:45:50 GMT

Which peer is losing the the bonding data -- nRF52832 or the phone? How many peers is the nRF52832 bonded with? Do you have a mechanism for removing bonding data (e.g. one of the DK buttons) that could be getting triggered?